Mr. W. T. Blanford on the Animals of Cijclostomacea, 55 



As the species are probably related to the Sponges, as sug- 

 gested by Huxley, they have considerable interest, and especially 

 the Spharozoa, which, like most Sponges, seem to have the power 

 of secreting silica. The extent to which the ocean, over an area 

 of many square leagues, was crowded with them, suggests that 

 such floating Sponges may have been, in past time, of geological 

 importance as one of the sources of silica for the flint or horn- 

 stone and siliceous petrifactions of ancient limestones and other 

 rocks. 



These species received from the author but a partial study, as 

 those of another class (oceanic Crustaceans) were engaging his 

 attention at the time. The above figures and descriptions are 

 from coloured drawings made on the spot, and from the notes 

 accompanying them. 



VII. — On the Animals of Raphaulus, Spiraculum, and othet^ 

 tube-bearing Cijclostomacea. By William T. Blanford, 

 A.R.S.M., F.G.S. 



No one can have examined carefully a collection of the opercu- 

 lated land-shells of India and South-eastern Asia without re- 

 marking the peculiar shelly processes of the peristome or suture 

 which characterize several of the genera. Two principal forms 

 of these processes may be distinguished, viz. (1) sutural tubes, 

 either open at both ends or closed at one extremity, as in the 

 genera Raphaulus, Spiraculum, Opisthoporus, Alycaus, &c. ; or, 

 (2) incisions in the peristome — simple, as in Pupina, Registoma, 

 &c., or accompanied by expansions of the outer lip, as in Ptero- 

 cyclos and Rhiostoma. So far as I am aware, no soft parts have 

 hitherto been observed, in the animals of any of the above ge- 

 nera, corresponding to the peculiarities of their shelly coverings. 

 During the past two or three years, I have examined carefully 

 the animals of species belonging to the majority of the above- 

 named forms ; and in two instances I have ascertained the exist- 

 ence of an organization to which the processes of the shell are 

 adapted, these two cases being in the genera Raphatdus and 

 Spiraculum, which, although by no means nearly allied, agree in 

 possessing a sutural tube opening both internally and externally. 

 By the kindness of Baron F. v. Richthofen, I had, some time 

 since, an opportunity of examining the animals of several speci- 

 mens of the rare Raphaulus chrysalis, Pfr., from Moulmein in 

 Burma. The sutural tube in this species opens internally, a 

 short distance from the peristome, by a small longitudinal slit, 

 and then passes outside the suture to the aperture, where it is 

 deflected upwards, and runs vertically for 2 or 3 millimetres on 



