PORIFERA. II. 



75 



A. biserialis R. and D. is a peimiform species provided with axial styli, reaching a length of 

 2""", and subtylostyli in the branches 044""" long. Of microsclera are found palmate anisochelse o-oi2 mm 

 long, and sigmata cro25 mm long. Unfortunately no anisochelse are figured, but they may certainly be 

 taken to belong to the form peculiar to the subgenus Asbestopluma. Its combination of spicules places 

 it nearest to Belgica, as sigmata and only one form of chelse are found in it, but the arrangement of 

 the lateral branches separates the two species sharply. Ridley and D e n d y do not mention any 

 stalk-coating, but there is some reason for believing that such a one is found; it may either have 

 been overlooked or wanting in their two specimens both of which were broken off below. 



A.Belgica Tops., as to its exterior, recalls bihamatifera\ accordingly it has branches issuing all 

 round, but the branches are arranged in groups of circles, and the groups are separated by naked 

 intervals. The number of circles in the group varies from five to ten, but the number of branches in 

 the circle is always six, and the branches are placed just over each other. The spiculation shows of 

 megasclera axial styli 14™™ long, with a little tapering upper end, and in the branches tylostyli ca. o-8 mm 

 long, further in the stalk-eoating curved, finely spinulous tylostrongyla of an average length of 0-2""". 

 The microsclera are anisochelse o-oi2 mm long and sigmata o - 033 mm long. Topsent's figure shows that 

 the anisoehelae are of the type characteristic of the subgenus Asbestopluma. This species, which is so 

 interesting with regard to its exterior, is by the spicula-combinatiou sharply separated from the other 

 species, with the exception of biserialis, to which in this respect it is closely allied. 



A. occidentalis Lambe is a species closely allied to citprcssiformis and lycopodiiaii, but separated 

 from these not only by the sizes of the spicules, but also by the skeletal structure, as it has, besides 

 a hollow middle axis of spicules, also an outer circle of spicula-fibres, while lycopodium, to which it 

 is most closely allied, has no such outer circle. Megasclera are styli growing to a length of r39 m,n ; 

 those found in the part of the branches inserted in the axis are given to a length of 0-41 — o - 68 mm ; 

 microsclera are anisochelse croi3 mm long, and forcipes o-032 mm long. From Lambe's figure of the 

 chela it cannot be decided with certainty that it is of the form typical of the subgenus Lycopod/i/a, 

 but this will certainly prove to be the fact. To judge from the figure, forcipes have a particular form. 



A. versa filis Tops. Top sent referred this species to the genus Forcepia, partly on account of 

 the fact that forcipes are found in it, and partly because he found embryos, in which he found diactinal 

 spicules which he took to be the dermal spicules of the species, which did not later develop further, 

 so that the}" were wanting in the grown sponge. The species is, however, surely an Asbestopluma of 

 the subgenus Cotylina, and seems to be closely allied to infundibulum, with which species it shows 

 some conformity both in its exterior and its spiculation. That it is an Asbeslopluina is seen from its 

 chelae, which, as far as can be seen from Topsent's figure, seem to belong to the Cotyli>ia-type, 

 and as forcipes are also found in this genus, their occurring here cannot solely justify the referring 

 to Forcepia. Also its anisochelse tell against referring it to this genus, as all the other Forcepia- 

 species have isocheke. With regard, finally, to the embryonic spicules, I do not think that the 

 forms figured by Top sent recall the dermal spicules of the Myxillina. Quite similar spicules, as 

 will have been seen, are found in the embryos of infundibulum, they are only more irregular, and also 

 monactinal spicules are found between them. To be sure, the question is here of embryonic spicules 



