DINOCHARID^E. 71 



three genera is also very different, and Stephanops has two eyes remote from the 

 mastax, while Dinocharis and Scandium have but one, closely applied to it. In all, 

 however, the trophi are symmetrical, the family differing widely in this respect from the 



Rattulidce. 



Genus DINOCHARIS, Ehrcnberg. 



GEN. CH. Lorica vase- shaped, dense, shagreencd ; facetted, and with projecting 

 plates, or armed dorsally with spines ; head retractile within a chitinous cap ; eye single, 

 apparently attached to the mastax ; foot and toes very long, the former bearing spines. 



Two of the species of this genus, viz. D. pocillum and D. tetractis, resemble each 

 other very closely ; the main difference being that the former has, on the last joint of 

 the foot, a small spine between the two toes. But the third species, D. Collinsii, is 

 strikingly unlike the other two, in several respects. Their loricae are vase-shaped, 

 facetted and spineless ; whereas its lorica is quadrangular, much depressed, free from 

 facets, but notched round its edge and bearing long dorsal spines. The head-coverings 

 are also unlike. Those of the first two species consist each of quadrantal pieces that 

 can be brought close together so as to enclose completely the withdrawn corona ; but in 

 the latter species the head is protected on the dorsal surface by a notched shelly hood, 

 and is uncovered on the ventral surface. 



D. POCILLUM, Ehrcnberg. 

 (PL XXL fig. 1.) 



Dinocharis pocillum . . . Ehrenberg, Die Infus., 1838, p. 472, Taf. lix. fig. 1. 

 ... Grenadier, Sieb. u. Kull. Zeits. Bd. xix. 18G9, p. 497. 



SP. CH. Lorica vase-shaped, sub-cylindrical, facetted, without spines ; foot and 

 toes very long, and together nearly twice the length of the trunk ; spurs curved ; a short 

 spine between the toes. 



The vase-shaped lorica of this species has a flat portion with scalloped edges down 

 the centre of its dorsal surface ; and a similar, but somewhat protuberant, portion on the 

 ventral surface. These two plates are connected by stippled concave surfaces, which 

 pass from a dorsal scallop to a ventral one and meet each other in stout transverse 

 ridges, which are very prominent in a side view ; and, when the creature is viewed 

 directly in front, so as to obtain transverse views of the trunk, it is evident that the 

 lorica, as shown in the elegant figure Ic, is produced on either side into delicate wing- 

 like plates at right-angles to its surface. The head is protected by a complete cap, con- 

 sisting of two pieces, which can fit together closely so as to conceal the corona, or fall 

 back on each side into a fold in the neck in order to permit the head to protrude. The 

 loricated foot, which is as long as the trunk, has three joints ; on the last of which are 

 tAvo slender toes, decurved, bent outwards, and as long as the foot itself. Between the 

 toes is a short chitinous spine. The first joint bears two stout spurs, usually about 

 as long as the joint that bears them, but occasionally more than double the length. 

 The front is rounded and set with small cilia : it is difficult to say what is the exact 

 structure of the corona, or the arrangement of the ciliary wreath. There are a large 

 mastax with sub-malleate trophi ; two conical gastric glands ; a broad cylindrical 

 stomach ; short intestine ; moderate ovary ; and very large contractile vesicle. This 

 latter lies athwart the body when distended, and in that condition fills up more than one- 

 third of the body-cavity : its time is four minutes. The lateral canals can be readily 

 seen on the ventral surface, but I detected only one vibratile tag. There is a large 

 crimson eye on the under surface of the nervous ganglion, which overlies the mastax so 

 that the eye seems attached to this latter. Dr. Grenadier (loc. cit.} has seen two lateral 

 rocket-headed antennae on each side of the lower third of the dorsal surface. 



This is an elegant and curious creature. With its toes well apart like a pair of com 



