STRUCTURE OF THE MARINE POLYZOA. 3 



other Loxosomas, which in their adult state are destitute of the 

 gland (L. singulare and L. Kefersteinii), form no such secretion, 

 but fix themselves by means of a sucker which terminates the 

 peduncle. 



The peduncular gland of L. Tethyce is imbedded in a three-lobed 

 terminal enlargement of the peduncle, and is composed of five or 

 six large pyriform cells, with large nucleus. Each of these cells 

 is prolonged into a very fine canal that unites with its fellows 

 into a common tube, which traverses the middle lobe of the pe- 

 duncular enlargement, and here opens externally by a pore. 



It is a remarkable fact that even the species of Loxosoma 

 which when adult do not possess the peduncular gland, have it 

 when young. The observations of Nitsche have proved this for 

 L. Kef erst einii ; and Salensky has confirmed it in the case of 

 L. crassicaiida, and Vogt in that of L. phascolosomatum. 



The cup-shaped body of Loxosoma has its margin directed ob- 

 liquely to the vertical axis, thus differing from the condition of 

 the same part in the other genera, where the margin of the cup is 

 transverse to the axis. Its wall consists, like that of the peduncle, 

 of a layer of nucleated cells which forms the endocyst, overlain 

 by a homogeneous membrane which corresponds to the ectocyst. 



The body-cavity, as in all the Endoprocta, is filled with a con- 

 tinuous parenchyma. This consists of cells apparently destitute 

 of membrane and provided with processes, which, by their union 

 with one another, form a network between the body- walls and 

 the contained organs — a condition which would seem to be uni- 

 versal among the Endoprocta, and which separates them by a 

 well-marked character from the Ectoprocta. 



The form of the tentacles is that of a prism whose inner or oral 

 side is provided with a ciliated groove. The outer side is com- 

 posed of a layer of flattened cells, quite similar to those forming 

 the outer layer of the body-walls. The axis of the tentacle is 

 occupied by a parenchymatous tissue like that which fills all the 

 body of the animal. 



Large unicellular glands are described by Salensky as dispersed 

 in the body-wall of L. crassicauda and L. Tethyce. They are 

 easily detected, being of a blackish colour and in considerable 

 number. They occur chiefly at the edge of the cup and base of 

 the tentacles, and consist of pyriform cells having their narrow 

 ends turned towards the free surface of the body. Each cell is 

 filled with a brownish finely granular matter enveloping a sphe- 

 rical nucleus. 



