804 RECORD OF CURRENT RESEARCHES RELATING TO 



After reminding the reader that the so-called lateral organ has, by 

 the latest researches, been seen to be composed of a number of 

 ganglionic cells and of a fibrous cord, together with a ganglion in- 

 vested in a membrane of connective tissue, and that there lies in it a 

 blindly ending ciliated canal, the author states that, as to this last, it 

 forms in the first third of its course a wide cylindrical vestibule, which 

 suddenly narrows. At the two points where the lumen of the canal 

 is constricted, there are to be found the orifices of a number of long, 

 fine efferent ducts, which pass ofi" from the unicelhilar glands, and are 

 massed together on the surface of the ganglion. The cilia which line 

 the canal work towards the blind end. The structure of the narrower 

 portion of the canal is somewhat remarkable ; there is a layer of 

 longish, compressed, rod-shaped corpuscles, set almost completely at 

 right angles to the lumen ; these rods ajjpear to be the bases of the 

 projecting cilia. The special investment of the canal would appear 

 to be a specific sensory epithelium, modified from the ordinary tegu- 

 mentary layer, while the gland cells have been pushed inwards 

 (downwards) by the ganglionic masses of the lateral organ, and further, 

 have become localized to two distinct points, where, clearly enough, 

 they take on the function of defending the sensory epithelium. 



As to the proper sensory organ, the function of which is not 

 known, the author suggests that, as in so many other aquatic and 

 marine forms, we have to do with a rudimentary organ which has 

 some function in relation to the character of the water. He is re- 

 minded by what he has seen in the Nemertinea of the organ of 

 Lacaze-Duthiers in the fresh- water Pulmonata, and he is supported 

 in his view by the fact that just as one organ is absent in the terres- 

 trial Pulmonata, so is the other in the terrestrial Nemertinea. 



The enteric epithelium consists of glandular and of elongated 

 absorptive cells ; the latter contain a number of highly refractive 

 spheres, which appear to be of an albuminous nature, and are appa- 

 rently drops of digesting food. Between the circular muscular layer 

 and the epithelium there is, in all the Nemertinea, a more or less well- 

 developed layer of connective tissue, which is distinguished by the 

 author as the subtegumentary connective tissue ; it has been described 

 as a " basilar membrane," but it is provided with distinct corpuscles, 

 and is not structureless. In all Anopla the nervous system seems to 

 lie between this tissue and the circular musculature ; in the more 

 differentiated Enopla it lies beneath the circular muscles. 



The excretory system of Tetrastemma is described as possessing 

 two long primary trunks, which, anteriorly, pass into an elaborate 

 coil of loops lying behind the cerebral ganglia ; among others, there 

 pass off from this coil an efferent duct, which opens to the exterior, 

 just behind the brain. 



Dr. Hubrecht publishes a note * stating that he finds only in the 

 Hoplonemertini a periphei'al nervous system, where it has the form of 

 regular dichotomously branching trunks arising from the lateral nerve- 

 trunks ; in Carinella, which Dr. Hubrecht looks upon as being the 

 most primitively organized genus of the Palteonemertini, there is, 

 * ' Zool. Anzeig.,' iii. (1880) p. 400. 



