296 



F. F. LAIDLAW. 



Thysanozoon plehni is on the whole most closely related to Th. obscurum described by 

 von Stummer-Traunfels [14] from Amboina. 



Genus Pseudoceros. 



A. Forms with a pair of penes. 



8. Pseudoceros gardineri sp. n. (PL XIV. fig. 4). 

 One specimen from Hulule, Male Atoll. 



Total length about 35 mm., total breadth about 22 mm. Mouth opening 8 mm. behind 

 the anterior margin. Female gonopore about 5 ram. behind the mouth. Sucker 7 mm. behind 

 the female gonopore. 



The margin is much folded. Body flat, oval with a prominent mid-dorsal longitudinal 

 ridge. Colour: dorsal surface a delicate gray with scattered irregular 

 black marks of varying size dotted over the surface; under surface 

 grayish-white. 



The marginal tentacles are sharply pointed, large and prominent. 

 The eyes, which are exceedingly numerous, are grouped as follows. 

 A large compact cluster containing about 200 eye-spots lies over 

 the brain. This is circular in shape save for a slight notch in the 

 middle of its hind margin. On the dorsal surface of either tentacle 

 near the middle line and close to the anterior margin is a group 

 of eyes, rather more scattered than those of the brain-cluster. On 

 the outer side of each of these clusters is a second still more diffuse 

 group. On the ventral surface of the tentacles, almost immediately 

 under the more medially placed dorsal group, are two roughly square 

 compact patches ; from the outer side of each of these a small 

 ' wing ' runs on to the ventral side of the tentacles (Fig. 68). The 

 projecting ' wing ' is concealed by marginal folds. 



9. Pseudoceros punctatus sp. n. (PI. XIV. fig. 5). 



One specimen from Hulule, Male Atoll. 



Total length about 30 mm., breadth about 17 mm. Mouth about 5 mm. from anterior 

 margin. Female gonopore 4 mm. behind mouth. Sucker 4 mm. behind female gonopore. 



Body oval, flat, with well-marked, median, longitudinal ridge. Colour pale grayish-yellow, 

 plentifully spotted on the dorsal surface with small black chromatophores. 



The tentacles are pointed as in the preceding species. 



The eyes over the brain form a very small cluster of some 25 — 34 minute eyes. At 

 the base of each tentacle, on the dorsal side and close to the anterior margin, is a small, 

 ill-defined cluster of eyes, and there are also a few scattered eyes on the outer sides of the 

 tentacles. On the ventral side of the tentacles are a pair of small clusters near the middle 

 line and a few scattered eye-spots along the tentacle fold. 



The species is readily distinguished from the preceding by its possessing much more distinctly 

 defined and more regular chromatophores, as well as by the relative fewness of its eyes. It 

 yet resembles it especially in the shape of the tentacles, which are more like those found 

 in certain Euryleptidae than those of most Pseudoceridae. 



FiQ. 68. Ventral surface of 



Pseudoceros gardineri. 

 p/i. = pharynx, s. = sucker, 

 u(. = uterus, i i = penes, 

 ? = female aperture. 



