PLATE 42. 



Fig. 1. 582. 1. Thysanocrinus liliiformis. (Pag. 188.) 



1 a. An imperfect specimen of the head of this species, with a portion of the column attached. 



1 b. The structure of this species; tlie upper portion of the figure including to the base of three of the arms, 



and the continuation of two of them made out from the exposed side of the specimen fig. 1 a. 

 1 c. A portion of one of the fingers enlarged, showing only one side with the tentacula attached. 

 1 d. The base of the fingers enlarged, showing the commencement of the double series of fjlates. 

 1 e. A single scapular plate enlarged. 



1 /. A portion of the column enlarged, showing the alternation of one thick plate with two thinner ones, 



and, below this, of one thick and one thin one. 



Fig. 2. 583. 2. Thysanocrinus canaliculatus. (Pag. 189.) 



2 a. A fragment of one of the fingers, showing the tentacula on one side. 



2 b. Two joints of the same enlarged, showing attachment of tentacula, form and proportion of joints, etc. 

 2 c. The exterior of the finger enlarged, showing the union of two series of joints. 



2 d. Vertical section enlarged, showing the jjosition of the contracted tentacles. 



Fig. 3. 584. 3. Thysanocrinus aculeatus. (Pag. 190.) 



3 a. The upper part of a crinoid, showing the contracted fingers and tentacula, five of %vhich are seen in the 



figure. 

 3 b. An enlargement of the back of a part of one of the fingers, showing the joining of the plates. 

 3 c. Several joints of the finger enlarged, showing the tentacula attached, the form, etc. of tlie joints. 



3 d. Several joints from another individual enlarged, showing the first joints of the tentacula to be less 



extremely alternating than in fig. 3 e. 



Fig. 4. 585. 4. Thysanocrinus immaturus. (Pag- 191.) 



4 a, b. Lateral view of the specimen, natural size and enlarged. 



4 c. The upper margin of the broken cup. 4 d. The base of the cup, natural size. 



4 e. Showing the structure of the cup, and form of the plates as far as the divisions of the arms. 



4 /. The base enlarged, showing the relations of the first and second series of plates, leaving out of view the 



overlapping edges of the latter. 



Fig. 5, 6. 586. 1. Myelodactylus convolutus. ( Pag. 192.) 



5 ffi. A fragment rolled together, forming more than a single convolution. 



5 b. Three joints of the finger enlarged, showing the tentacula to the fifth joint. 



6 a. A fragment of a similar finger, showing the broad groove on the inner side, and the minute perforations 



on the truncated inner angles of the plate. 

 6 b. The outer side or back of the same fragment, showing a nodulose surface. 

 6 c. Several joints enlarged, showing the character of the inner side. 



6 d, e. The back enlarged, showing in e the minute groove for the passage of a tendon to the external surface. 

 6/', g. Articulating surface of the plates, natural size, from two different specimens. 



6 h. The same enlarged, showing the form of canal, the pentagonal muscular impression with ridges for the 



attachment of muscles, and the minute grooves extending to the back of the column. 



Fig. 7. 587. 1. Dendkocrinus longidactylus. ( Pag. 193.) ' 



7 a. A specimen of this species, \y\i\i the arms broken off, but preserving a large portion of the long pro- 



boscis which is flattened. 



7 6. A portion of the proboscis enlarged, showing the form and arrangement of the plates of which it is com- 

 posed. 



7 c. Portion of the upper part of the column enlarged. 7 d. Section of the bus. of the cup. 



