Pachinion scriptum
Roemer 1864
Pachinion scriptum is one of the more common sponges.
It is usually pear- or club-shaped, with an oscule 5 to 8 mm wide. Several individuals may be intergrown, as in the two pictures to the left. Commonly, the size is on the order of 50 to 100 mm.
Parts of the surface (dark areas), particularly near the base, are usually covered with a dense layer (cortex), which is covered with numerous star-like dichotriaenes. The other areas show a coarse network made up of dicranoclones with wart-like surface sculpturing, grading into rhizoclone-like forms.
The example to the left is almost completely covered with a cortex, but shows three strips where the cortex is lacking. These are probably injuries inflicted by a predatory organism, such a slug or a star fish.
The picture shows typical scleres of Pachinion scriptum (after Schrammen, 1910).
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(a) dicranoclones
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(b) megarhizoclonides
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(c) siliceous particle of covering layer
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(d) dichotriaene
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(e) rod-shaped spicules of covering layer
The plate shows some typical examples of scleres of Pachinion scriptum .
Rows 1 through 3: Dicranoclones and one megarhizoclonid
Row 4: Dermal dichotriaenes.
Microphotograph of an HCl-etched sample of Pachinion scriptum showing skeleton composed of heavily warted dicranoclones.
Pachinion cylindricum
Schrammen 1901
Pachinion cylindricum occurs in cylindrical habits, but is otherwise very much like Pachinion scriptum. It is quite rare.
Schrammen (1910) noted that the spicules of Pachinion cylindricum appear to be slightly larger than those of the other Pachinion species.
Pachinion familiare
Roemer 1864
Pachinion familiare appears to differ from Pachinion scriptum only by the degree of intergrowth of various individuals. In Pachinion familiare the individuals are only recognizable by the number of paragaster outlets, while their bodies have merged into one compact body. The species status seems therefore questionable.