MR. A. DENDY ON WEST-INDIAN CHALININE SPONGES. 



359 



appear altogether, leaving only the horny fibre, a circumstance to which I have already 

 referred, and with which I shall have to deal more fully later on. 



Duchassaing and Michelotti have arranged the species of the genus in three groups, 

 according to the nature of the mouth of the tube, as follows: — 



C Tissu fin, surface exterieure munie de 

 I processus spiniformes encroutes. 



Orifice du Siphon forte- 

 ment cilie. 



Tissu grossier, surface exterieure herissee 

 de pinceaux de fibres non encroutes. 



Orifice du Siphon plutot frange que cilie 



Orifice nu, c. h d. n'offrant ni cils ni pinceaux bien formes, ni franges . J 



f Tuba. Sancta crucis. 

 Sororia. 

 Conica. 

 Lincata. 

 Megastoma. 

 Bursaria. 

 Armigera. 

 Digitalis. 

 Incesta. 

 Pavonina. 

 Crispa. 

 Longissima. 

 Vaginalis. 

 Lsevis. 

 Subenervia. 

 Plicifera. 

 Scrobiculata. 

 Irregularis. 

 Sagoti. 



The material at my disposal is sufficient to show in a very conclusive manner that 

 this arrangement of the species is a very unsatisfactory one. There is in the collection 

 a specimen of Spinosella {Tuba) sororia, var. elongata, mihi, consisting of about thirty 

 tubes, some of which are " ciliated " at the orifice while others are "naked." Indeed, 

 this appears to be a character of but slight importance and even of extremely doubtful 

 specific value, and it is, consequently, rather surprising that so practised an observer 

 as Mr. Carter should have adopted it 1 , more especially considering that Schmidt 2 had 

 already come to the same conclusion as myself with regard to its value and for a pre- 

 cisely similar reason. 



The genus Spinosella is very closely related to Schmidt's Siphonochalina, and it is 

 an open question whether or not the two should be united. The degree of develop- 

 ment of the spines on the surface varies much even within the species. Thus, in my 

 variety elongata of Duchassaing and Michelotti's species sororia, the spines are almost 

 entirely obsolete, while in the typical form and in other varieties of the same species 

 they are strongly developed ; and yet, as will be seen later on, there are so many 



1 Ann. & Mag. Nat. Hist. ser. 5, vol. ix. p. 278. 



2 Spong. atlant. Gebiet. p. 34. 



3 f2 



