632 WILLIAM A. HASWELL. 



Of the four specimens received three are sexually mature, 

 and agree with one another in all essential points ; the fourth, 

 somewhat smaller than the rest, differs from them in the 

 rudimentary condition of the reproductive apparatus. In none 

 of them is the state of preservation very perfect in all respects, 

 and the following description is necessarily incomplete in a 

 good many points. I am also unable, owing to a good many 

 gaps in our Sydney scientific libraries, to attempt to deal in 

 any complete manner with the literature. 



The total length of the largest specimen is 2*5 cm., and the 

 greatest breadth 4 mm. No pigment is present in any part, 

 and there are no eyes. The body (fig. 1) is elongated, con- 

 siderably depressed, thick in the middle where tlie alimentary 

 canal and other organs lie, thin at the sides ; these lateral thin 

 regions assuming the character of thin solid longitudinal 

 flanges. The anterior extremity is broad and truncate, the 

 antero-lateral angles produced into small compressed projec- 

 tions; the posterior portion of the body tapers to a blunt 

 point. The mouth is a wide aperture at the anterior end. 

 The openings of two ciliated sacs (c. s.) are situated on the 

 ventral surface, a little behind the antero-lateral angles. The 

 two excretory apertures {ex.) are situated on the ventral 

 surface, some distance apart, a little in front of the middle 

 of the body. The female generative aperture (?) is also 

 situated on the ventral surface in the middle line, some little 

 distance behind the excretory pores. 



Integument, Integumentary Glands, Muscular 

 Layers, and Parenchyma. — The specimens are not in a 

 sufficiently good state of preservation to permit of a detailed 

 investigation of the structure of these parts, and the following 

 account is necessarily incomplete. The presence of vibratile 

 cilia on the surface cannot be determined with certainty ; but 

 elevations of the integument, the arrangement and structure 

 of which remain uncertain, bear, singly or in groups, long 

 straight cilia, probably of a non-motile and sensory character. 

 The cuticle (fig. 3, c.) is '002 mm. in thickness; it does not 

 appear completely homogeneous, but exhibits indications of 



