30 H, N. MOSELEY. 



In the younger stage (PL III, fig. 2) the body was of the 

 oidinary flat form of Planarians, 1 mm. in length, and was pro- 

 vided with three short body processes on each side bearing 

 long cilia. On the general body surface the cilia Avere very 

 minute indeed. Brightly pigmented cells with oily contents 

 were scattered sparsely over the body in the epidermis. 

 These were coloured either burnt-sienna colour, bright pink, 

 or yellow, recalling to mind the pigmented bodies in the 

 retinas of birds and reptiles. The pharynx and nerve ganglia 

 were Avell defined. 



In the more advanced stage the head of the larva, which was 

 2 mm. in length, had assumed an abruptly squared form. Over 

 the anterior and middle region of the body the pigment cells 

 were grouped in patches in the epidermis, separated by inter- 

 vals free of them, whilst towards its hinder extremity they were 

 dispersed. The body was expanded at the region where the 

 processes are given off, and gradually narrowed behind it. The 

 processes were much longer than in the earlier larva. Although 

 only three pairs of processes are here figured, a dorsal and 

 a ventral process were also present, as in MiiUer's larva ; but 

 they are not shown in the figure, because it is taken from a 

 somewhat compressed specimen. On the processes the long 

 cilia were borne by large transparent cells with nucleus and 

 nucleolus (fig. 3), which were nearly spherical in form, with a 

 diameter of "O^ mm. and fine granular contents. These cells 

 were highly contractile, and shoAved a constant tAvitching of 

 their Avails. The commencing differentiation of the digestive 

 tract Avas marked out by straight elongate masses of cells, 

 disposed in a radiating manner, and Avell defined by their 

 opacity. The larva Avas of a dark, blackish apiDcarance ; its 

 body mass Avas mainly composed of cells, such as figured in 

 fig. 5. In the integument Avere abundance of rod cells. The 

 rods are packed in the cells exactly as in a Thysanozoon 

 occurring at Zamboangan, i. e. so as to form a holloAV cylin- 

 der inside the cell (fig. 6). About ten rods occur in each cell. 

 The rods (fig. 2) are somewhat oat-shaped, Avith a groove 

 doAvn the middle line of each face, so that their section is as 

 shoAvn in fig. 8. The pigment cells are disposed amongst the 

 rod cells in the epidermis (fig. 4), together Avith a few elon- 

 gate, transparent, colourless cells. The pigment cells are 

 all provided Avith a nucleus, and arc some spherical, some 

 ovoid. 



From the occurrence of this larva in a harbour, in abun- 

 dances Avhere a Thysanozoon Avas also found abundantly, 

 from the structure of its peculiar rod bodies being iden- 

 tical with those of the Thysanozoon, and from its contain- 



