SPECIMENS OF CKYPTOLITHUS. l6l 



what less fully developed than at present. On plate 9 are two figures in which specimens 

 235 and 236 are brought together again, and both dorsal and ventral sides illustrated. 



On the dorsal side, specimen 235 shows portions of three exopodites which lie in a 

 direction roughly parallel to the outer portions of the endopodites on the lower side, that is, 

 their direction if projected would reach the axis in an acute angle back of the end of the 

 pygidium. The seta? stand at right angles to the shaft, and on a portion of it 0.5 mm. long 

 there are seven of them. This is a fragment of an exopodite near the front of the thorax, 

 and the setae, which are flattened, are about 1.63 mm. long. 



On the ventral side this same specimen shows incomplete endopodites and exopodites of 

 about seventeen segments, six of which would belong to the thorax and the remainder to 

 the pygidium. The greater part of the appendages belonging to the pygidium are exceedingly 

 small (about 0.15 mm. long) and so incompletely exposed that the structure can not be 

 definitely made out. 



The endopodites of the thoracic segments all lack the greater part of their proximal 

 segments and are all of practically the same form. They turn abruptly backward at the 

 outer end of the meropodite, and the carpopodite of each is greatly widened, projects inward 

 and is armed with tufts of spines. The propodite and dactylopodite are wide, flattened, 

 and taper but slightly outward, the dactylopodite bearing on its distal end a tuft of spines. 

 On several of the endopodites, the meropodites are visible and they bear on their inner ends 

 fringes of spines pointing inward. Behind these well preserved appendages the proximal 

 segments of several endopodites are visible, and a regular succession of flattened, oval bodies 

 armed with numerous forward-pointing spines. These latter bodies Professor Beecher took 

 to be leaf-like exopodites, which they certainly resemble, and as they lie beyond the line of 

 endopodites they probably do belong to the outer halves of the appendages. 



The exopodites under the thorax are long, the shaft shows numerous short segments, 

 and is in each case bent backward, though not through a right angle. They extend consid- 

 erably beyond the endopodites. The seta? do not diverge from the shaft at a right angle 

 as on the dorsal side of this same specimen, but at an acute angle, indicating that they were 

 not rigid. The individual hairs are broad and blade-shaped, frequently with a linear depres- 

 sion along the median line, perhaps due to collapse of the internal tube. 



Measurements: The greatest length of the fragment in its present state is 5 mm. The 

 dactylopodite of the second endopodite (without terminal spines) is 0.18 mm. long, the propo- 

 dite 0.23 mm. long and 0.15 mm. wide; the carpopodite is 0.24 mm. long and 0.38 mm. wide. 

 All measurements were made on the photographs. 



' Specimen No. 236 (pi. 7, figs. 3-5; pi. 9, figs, i, 2); (text fig. 45). 



The right half of the same thorax and pygidium as specimen No. 235. 



The specimen is cleaned from both upper and lower sides and, the dorsal test being re- 

 moved, reveals the long blade-like seta? of the exopodites, each blade being concave along 

 its median line. They are long on the exopodites of the thoracic segments, but become shorter, 

 without, however, any visible change of form on the pygidium. Although the posterior end 

 is not well preserved, one gets no suggestion from a study of this side of the specimens that 

 the exopodites of the posterior end are in any striking way different from those of seg- 

 ments further forward. The tips of some of the seta? show minute spines, one to each 

 blade. 



