110 Prof. Carl Glaus on the 



in the form of bacilli on the visual cells of Cypridina, which 

 are turned towards the pigment, but within, turned towards 

 the pigment, 1 have found a second layer of narrow elongated 

 nuclei, which must belong to a special form of cells. The 

 rounded nuclei of the nerve-cells are placed peripherally, 

 turned towards the entering nerves and the overlying secre- 

 tion-lens, which is clothed by the delicate integument. In 

 Notodromus the three divisions of the frontal eye are sepa- 

 rated from each other, and here, as in the Pontellce and Onis- 

 cidice among the Copepoda, we have an anterior, ventral, cup- 

 shaped eye and two separated lateral eyes, which are easily 

 distinguished from the composite lateral eyes. 



3. EndosJceleton. — Beneath the oesophagus, between the 

 stomach and the anterior ganglionic mass of the ventral cord, 

 in front of the transversely placed sinew of the shell-muscle, 

 there is a broad, indistinctly bipartite, chitinous plate, upon 

 which, in agreement with the endoskeleton of the Phyllopoda 

 and other Crustacea, as also with the so-called endostomite of 

 the Arachnoidea, pairs of muscles for all the limbs of the 

 trunk, including the second pair of antennse, are attached. 

 On its anterior margin originate numerous muscular threads, 

 which pass to the lower wall of the oesophagus, and two slender, 

 long, muscular bundles, which pass through the space between 

 the mandibular and maxillary ganglia to the labium. 



4. The alimentary apparatus commences by a rather nar- 

 row atrium, bounded by the labrum and labium, into which 

 the toothed biting edge of the mandibles enters from the right 

 and left. Zenker's " rake-like masticating organs " are 

 situated at the bottom of it, and belong, as a sort of hypo- 

 pharynx, to the labium. In the bottom of the atrium beneath 

 the labrum commences the buccal intestine, ascending at 

 first nearly perpendicularly and then somewhat obliquely 

 backwards to the stomach. The shorter anterior part of it 

 (oesophagus), which is about equal in length to the atrium, 

 appears to be nearly cylindrical, but with a more strongly 

 arched ventral wall^ into which the pair of muscles springing 

 from the endoskeleton and acting as dilaters enter. More 

 numerous and larger muscles pass from the integument of the 

 labrum to the flattened dorsal surface of the oesophagus, and 

 draw up its very thick wall, the convex surface of which 

 projects like a valve into the lumen, and thus, in conjunction 

 with the dilaters of the lower oesophageal wall, enlarge the 

 lumen, which is horseshoe-shaped in transverse section. The 

 following larger division of the oesophagus (gizzard) appears 

 to be essentially altered in form ; it was described by Zenker 

 as a very complicated triturant organ, resembling the human 



