404 Th. Mortensen. 



carefully reexamined the excretory organs of both L. crassicauda and 

 annelidicola and found them in both forms to be intracellular tubu- 

 les ending in a flame-cell. His suggestion that all the Entoprocta 

 will prove to have their excretory organs built on this type seems 

 quite justified. — In any case I would suggest that these two species are 

 more nearly related to each other than to any of the other species 

 referred to the genus Loxosoma, with the exception, probably, of L. 

 singulare Keferst. (see below). Nickerson certainly thinks that L. Da- 

 venporti resembles most closely L. crassicauda, mentioning among 

 other characters in which they agree the absence of a foot-gland. 

 (Op. cit. p. 373). This is, however, a mistake, L. crassicauda having 

 the foot-gland well developed in the buds. 



It is very probable that also L. singulare Keferstein belongs to 

 this group. Claparède (Beobachtungen über Anatomie u. Entwick- 

 lungsgeschichte wirbelloser Thiere. 1863. p. 106) states that "die ganze 

 Sohle mit zahlreichen .... rundlichen Zellenkernen besetzt ist, die 

 unmittelbar unter der farblosen Cuticula sitzen", and that the basal 

 part of the foot is developed as a sucking disk Ч This makes it 

 л^егу probable that the structure of the foot is really as in L. anne- 

 lidicola and Davenporti ; but]there are, unfortunately, no observations 

 showing, whether oblique muscles are present or not, and it is not 

 definitely shown either, whether a foot-gland is possibly developed 

 in the buds. 



Another natural group of species would appear to be formed 

 by those in which the foot-gland persists through life, viz. L. nepoli- 

 taum Kowalevsky, L. raja Schmidt, L. tethyæ Salensky, L. alata Bar- 

 rois (=-- L. pes Schmidt), L. leptoclini Harmer and L. Harmeri Schultz. 

 Possibly this group should be further subdivided after the shape of 

 the foot, it being more or less wingshaped widened in L. raja, lethyœ 

 leptoclini and alata, while in L. nepoliiaum and Harmeri it is not 

 thus widened. 



A few species are still left, viz. L. cochlear Schmidt, L. claviforme 

 Hincks and L. Nitschei Vigelius. These are so insufficientlj^ known 

 that it is impossible to say to which group they belong^^'. 



I would think it not unreasonable to regard these different 

 groups as separate genera. The first species described of the genus 



' E Schultz. Loxosoma Harmeri. Travaux de la Soc. Imp. des Nat. St. Peters- 

 bourg, XXV. 1895 p. 55. states that L. singulare has a foot-gland; but this must be a 

 mistake. 



- In K. Derjugin. Zur Kenntniss der Fauna des Kola-Fjords. Die Arbeiten an 

 Bord des Jacht „Alexander Kowalevsk}", im Jahre 1909. (Vorl. Mitteilung! И- (Trav. 

 Soc. Imp. Nat. St. Pétersbourg XLII. 1911. p. 23 and 43) are named Loxosoma koiva- 

 levskii Kl. n. sp. and L. normanni Kl. п. sp , without any description or figures. 

 Thev are thus onlv nomina nuda. 



