108 R. C. PUNNETT. 



The epithelium is somewhat low, and the nuclei form a well-marked layer at the 

 bases of the cells. In the outer clear portion of the cells are a few unicellular glands, 

 which take a vivid yellow stain with picric acid. A very thin basement membrane separates 

 the epithelium from an exceedingly delicate layer of circular muscle fibrils. Below these 

 again come a few longitudinal muscle fibrils, which are separated from the outer longitudinal 

 muscle layer by a layer of nuclei, apparently representing the cutis glands. The pigment, 

 which gives rise to the black markings of the worm, is situated partly in the cutis (PI. V. 

 fig. 1) and partly in the nuclear layer of the epithelium. The outer portion of the outer 

 layer of longitudinal muscles is more or less divided into bundles by strands of connective 

 tissue. 



Of the muscle layers of the body wall the circular muscle layer is rather thicker than 

 the inner longitudinal but less than half the thickness of the outer longitudinal layer. 

 There are well-marked horizontal fibres over the mouth. The precerebral region is more 

 closely packed with muscle fibres than is usually the case. There is no diagonal muscle 

 layer. 



The mouth commences shortly before the level where the cerebral organ terminates. 

 There is no ventral gutter to the intestine. 



The vascular system shews a well-marked cephalic head loop. The buccal commissure 

 is well developed. Shortly after the termination of the excretory tubules the oesophageal 

 lacunae are gathered together into a single small lateral lacuna which extends to the in- 

 testinal region. Here it acquires a coat of parenchyma cells, and gives off dorsal commissural 

 branches, becoming the lateral blood vessel. 



The proboscis is fairly well developed, and shews the three muscle layers characteristic 

 of the Lineid proboscis. Muscle crosses are present. 



The excretory system commences soon after the hinder termination of the mouth. There 

 is a median longitudinal tubule running along at the level of the nervous stem. Into it 

 smaller tubules open at intervals, extending a little way above and below the level of the 

 side stems. They are however both small and few in number, the whole excretory system 

 being much attenuated. There is a single duct (PI. V. fig. 10) on either side about the 

 middle. The lumen of these ducts is also reduced, and it is probable that they were not 

 functional in the living animal. 



No gonads are developed. 



The brain is not very large. The dorsal ganglia lie directly over the ventral which 

 are closely apposed. Both dorsal and ventral commissures are extremely short. The median 

 donsal nerve is well marked. Neurochord cells are present in the ventral ganglia though they 

 are not so large as usual. The cerebral organ is fairly well developed though the gland cells 

 in connection with it are somewhat scanty. It lies for the most part dorsal to and just 

 inside the nervous side stems. The head slits reach nearly to the brain and extend back- 

 wards to the level where the cerebral organ terminates. 



Numerous small eyes are present on the tip of the head just dorsal and ventral to 

 the head slits. Frontal organ and head glands are both absent. 



7. Gerebratulus gardineri, n. sp. (PI. IV. figs. 6, 9, and PL V. 2, 4, 8.) 

 Locality. Minikoi, Laccadive Is. From lagoon sand. 



