REPORT ON THE MONAXONIDA. 173 



Prince Edward Island; depth, 310 fathoms; bottom, volcanic sand. Fairly abundant 

 fragments, of a brown colour. 



Station 148, Januar}^ 3, 1874; lat. 46° 47' S., long. 51° 37' E.; Possession Island ; 

 depth, 210 fathoms; bottom, hard ground, gravel, shells. Two or three small, yellow 

 pieces. 



Genus Ciocalypta, Bowerbank (Pis. XXXIII. , XL.). 



1864. Ciocalypta, Bowerbank, Mon. Brit. Spong., vol. i. p. 179. 



Megasclera stylote and sometimes oxeote, forming a more or less dense central 

 skeleton (fibrous or reticulate) from which are given off pillars of spiculo-fibre nearly at 

 right angles. These spread out at their distal ends and support the dermal membrane, 

 with its reticulation of spiculo-fibre, at some distance from the central portion of the 

 sponge, thus leaving huge subdermal spaces into which the water enters through the 

 pores in the dermal membrane. No microsclera. 



Bowerbank's original diagnosis {loc. cit.) runs as follows : — " Skeleton. Composed 

 of numerous closed columns, each consisting of a central axis of compact, irregularly 

 elongated, reticulated structure, from the surface of which radiate, at about right angles, 

 numerous short simple, cylindrical pedicles, or stout fasciculi of closely packed spicula ; 

 the distal ends of each pedestal separating and radiating in numerous curved lines which 

 spread over the inner surface of the dermal membrane, separating and sustaining it at 

 all parts at a considerable distance from the central axis of the skeleton." 



In this diagnosis there is not a word as to the form of the spicules. The original 

 type of the genus is Ciocalypta penicillus, Bowerbank, in which the spicules are all 

 stylote. In Ciocalypta tylcri,^ Bowerbank, the spicules are all oxeote, but it seems very 

 doubtful whether this species is referable to the genus Ciocalypta^ at all. 



Bowerbank's Ciocalypta led,- represented by a single, minute, dry specimen, about 

 13 mm. in length and only about 3 mm. in greatest duimeter, must be regarded as a 

 young specimen of Ciocalypta penicillux, or at the most as a mere variety, and the 

 same remark applies to the specimen which has been called by Mr. Carter Ciocalypta 

 tuherculata {vide p. 175). There are thus (excluding the doubtful Ciocalypta tyleri) 

 three species of the genus now known, viz., Ciocalypta penicillus, Bowerbank, Ciocalypta 

 hyaloderma, nobis, and CiocalyjJta amoiphosa, nobis ; for -Ciocalypta calva,^ Eidley, is 

 wanting in one of the chief characters of the genus, viz., the characteristic arrangement 

 of the dermal skeleton ; and it also possesses a horny fibre. 



The genus differs from Axinella most markedly in the possession of a distinct, spiculo- 

 fibrous dermal reticulation, and further in the very large size of the subdermal cavities. 



• I'roc. Zool. Sue. Land., 1873, p. 21, pi. iv. figs. 9-12. 



2 Mon. Brit. Spong., vol. iii. p. 296, pi. Ixxxvi. figs. 1-4. 



3 Zool. Coll. H.M.S. "Alert," Proc. Zool. Soc. Load., 1881, p. 115, pi. x. fig. 7. 



