620 PEOF. W. A. HEEDMAN S BEYISED 



PsAMMAPLiDnjM, Serdman, 1886. 



Colony incrusting, massive, or lobed. 



Systems inconspicuous. 



Ascidiozooids usually small, not much elongated, and not dis- 

 tinctly divided into regions. 



Test thick, and greatly strengthened "by imhedded and in- 

 crusting sand-grains and other foreign bodies, which form a 

 great part of its bulk. 



Branchial sac small and not well developed. 



Postahdomen usually short. 



The species referred to this genus may be separated as 

 follows : — 



C Colony broken up into narrow branched and anastomosing strands. 



\ F. retiforme, Herdm. (A. Arct.) 



[ Colony not retiform 1 



, f Colonj' thin and incrusting 2 



\ Colony massive 3 



n r Colour dark brown P. effrenatum, Herdm. (S. Atl.) 



\ Colour stone-grey P. incrustans, n. sTp. (Austr.) 



o [External part of test forming a distinct layer 4 



\ External layer of test not modified 5 



I Colony formed of Ascidiarium on narrow peduncle. 

 P. peduncuJatum, n. sp. (Austr.) 

 Colony formed of irregular masses not pedunculated 6 



/, J Colony not lobed P. flavum.,'KevAm. (S. Atl.) 



Colony lobed 7 



( Central layer of test free from saud. 

 7 -^ . P. fragile, n. sp. (Austr.) 

 [ Sand all through test 8 



(Stigmata much wider than interstigmatic vessels. 

 P. soUdiim, n. sp. (Austr.) 

 Stigmata same width as vessels or narrower. 

 P. lobatum, n. sp. (Austr.) 



p. fColony ovate or pyrifortn 9 



\ Colony irregularly lobed ]0 



i Much imbedded sand ; colony quite stiff 11 

 Not much sand ; colony firm, but not stiff. 

 P. ovatum, Herdm. (Austr.) 

 f Shape ovate, colour green-grey, muscles weak, stigmata long. 

 ,, J P. subviride, Herdm. (S. Atl.) 

 I Shape pyriform, colour yellow-grey, muscles strong, stigmata short. 

 l_ P. pyriformis, Herdm. (Austr.) 

 C Short cylindrical lobes from common base, stigmata very narrow. 

 10 \ P. exiguum, Herdm. (S. Atl.) 



[ Lobes irregular, stigmata not very narrow 12 



(Stomach globular, smooth-walled ... P. spongiforme, Herdm. (Austr.) 

 Stomach quadrate, folded longitudinally. 

 P. rude, Herdm. 



