140 



PORIFERA. II. 



teeth, and 011 either side a narrow ala. The alae continue along the shaft, and in the middle they are 

 connected by a quite narrow rim; thus there is no free middle part of the shaft, but only an incision 

 in the rim running on either side. The ancorse are very varying in size, their length is between 0-0157 

 and o - 05 mm , and the breadth is proportionately 0-004— o-oi8 mm . The larger ancorse are most predominant. 

 Developmental forms in different stages were seen. 2. Sigma ta are of the common form and contort 

 in different degrees; their size is rather varying, the length from o - oi8 — o-032 nira , and the thickness from 

 ca. o-ooii — o-oo2 mm . Both forms of microsclera occur through the whole sponge and in no small numbers 

 in the dermal membrane. 



Remarks: Of this species I have for comparison had a fragment of one of Schmidt's type 

 specimens sent to me by Dr. Mark tanner-Turneretscher, and so I have been able to identify my 

 species with certainty. It is also quite in conformity to Lieberkiihn's description and figures I.e.; 

 especiallv the figure of the acanthostyli is exceedingly characteristic. On the other hand neither 

 Lieberkiihn nor Schmidt mentions the pluripointed ends of the tornotes, but they must also be 

 seen under very high magnifying powers to be made out distinctly. In Schmidt's type specimen the 

 megasclera are a little smaller than in my specimens; thus the styli have an average length of o-i6 mm , 

 and do not exceed o-iyS" 11 ", and the average length of the tornotes is o-i5 mra , and they do not exceed 

 Q.jygmm^ Schmidt describes later, under the M. tridens established by him in 1864 I.e., the three- 

 pointed tornotes very minutely, and compares very appropriately the form of their ends to the head 

 of an Ascaris. In 1868 he (Die Spong. der Kiist von Algier, 27) joins, and, no doubt, correctly, this 

 species to M. rosacea. When Vosmaer 1. c. further refers Schmidt's M. fasciculata here, and says 

 that this species is different from fasciculata Lieberk., I take this statement to be owing to a mistake. 

 An original preparation here in our museum of fasciculata, labelled with Schmidt's own hand, shows 

 that this is a quite different species, even a species with chelae arcuatEe, and a specimen of M. fasci- 

 al hi ta Lieberk. sent by Prof. v. Marenzeller, is quite agreeing with it as to spiculatiou. — Top- 

 sent maintains (Mem. de la Soc. zool. de Fr. VII, 1894, 16, the foot-note) that M. rosacea and M.iucru- 

 stans are identical. This, as will have been seen, is not the case; but it will appear from the following 

 how Topsent has arrived at this conclusion. The fact is that Topsent (Arch, de Zool. exp. et gen. 

 Ser. 2, V bis, suppl. 118), as before mentioned, under incrustans mentions two varieties of this species, 

 typica and viscosa, and while only var. typica can be identical with incrustans, var. viscosa, according 

 to Topsent's description, proves to be identical with rosacea. Topsent's description leaves no 

 doubt of the identity; he points out the pluripointed (Topsent says two-pointed) ends of the tornotes, 

 he mentions the red colour, and finally he says that var. viscosa differs from var. typica by the presence 

 of cellules spheruleuses> with large grains. Now the fact is that rosacea really has these cells in 

 exceedingly large numbers, they are seen in enormous quantities in the tissue, especially in the mem- 

 branes; they have a diameter of ca. o-oi4 mm , and are filled with few, large, somewhat refractive grains. 

 The M. rosacea var. japonica enumerated by Ridley and Dendy (Challeng. Report, XX, 130, 

 PI. XXVI, fig. 3, PI. XXVII, figs. 8,8 a— c, PI. XLVII, fig. 3) must, according to the description, be a 

 different species, and this holds also good of the M. rosacea var. mentioned by Lambe (Trans, of the 

 Roy. Soc. of Canada, X, sect. IV, 71:, PI. II, fig. 6, PI. V, figs. 6, 6 a — f), which has higly spined styli 0-24 

 — o-28 mm long and simply pointed tornota o-22 mm long. 



