128 



ZOOLOGICAL COLLECTIONS MADE DURING [Jan. 4, 



surface, tho openings being those of the excretory canals. Main ske- 

 leton of spiculo-fibre, the spicules uniterl by a minimum of sarcode, 

 consisting of a primary set of fibres, from 6 to 10 spicules thick, at 

 right angles to the surface, from which they project (multiplying as 

 they approach the surface by hrancMng), connected by a secondary set 

 at right angles to them, containing usually from three to four spicules 

 in their diameter, and by an irregular network of single spicules or 

 bispicular fibre, crossing the interspaces at various angles. 



Dermal Skeleton. An irregular reticulation, I to G spicules thick, 

 lying between the points of the primary-skeleton fibres in superficial 

 pigmented layer. Parenchyma semiopaque, muddy-brown in colour. 

 Spicules — but one form for all parts, viz. a smooth acerate, slightly 

 bent at the middle, ending rather gradually ; size •17736 by '00887 

 millim. Embryos, apparently in the i^lanula stage, lie embedded 

 near the interior surface of the Sponge ; they are oval ; the greatest 

 diameter varies from -24 to •43 millim. In one place a dense mass 

 of about 15 occurred. As the specimen was taken on March 3rd, 

 1879, the sexual period is hereby fixed. 



Examined. In spirit, and by mounting in balsam. 



Hab. Trinidad Channel, Chili (just north of chief island of Madre- 

 de-Dios archipelago), 30 fathoms. 



Ohs. The specimen differs somewhat from the original specimens 

 of the species, though hardly enough for it to form a new species. 

 The chief differences are here tabulated : — 



8. aulopora, West- | 

 Indian specimens ■{ 

 (^Schmidt). 



S. aulopora, 

 S.W. Chili. 



External Charac- 

 ters. 



/'Massive, sub- 

 erect ; Tents 

 along edge of 

 column, in dis- 

 tinct tubes. 

 Yellowisb in 

 dry state. 



( Massive ; vents 



on distinct tube 



or tubes. Dull 



var., ■{ brown in sjiirit. 



I 



Skeleton . 

 Primary^ lines pro- 

 ject slightly from 

 surface ; spicules 

 6- to 12-serial in 

 them ; secondary 

 liues5-to7-serial. 



Spicules. 

 Acerate, slightly 

 bent at middle, 

 tapering slowlyoff 

 to points. Sizo 

 •165 by -00792 

 mm. 



Primary lines pro- As in preceding. 

 ject considerably Size 'YllZQ by 



from surface ; spi- 

 cules 6- to 10- 

 serial ; secondary 

 lines 3- to 9- 

 serialc 



•00887 mm. 



The probable type specimen of Isodictya mirabilis, Bowerbank, 

 from the " East Indies," has spicules measuring -1771 by •0079 

 millim., and agrees well (apart from the presence of the polyp-cells) 

 with Schmidt's species in external characters, although the tendency 

 of the vents to become elevated on separate tubes towards the base 

 is but slightly marked. If the locality for that species is correct, 

 the distribution is a very wide one— assuming the identity of the 



' It should be noted that the specimen from which the character was tak en 

 was pi'obably dried before being monnted; therefore the ends of the fibres 

 had probably been rubbed. 



