PLATE XIV. 



Development 0/ Decapoda, continued. Figures from Walter Faxon and Carl Glaus. 



1-4. Carcinas mcenas (continued from PI. XIII.). From Faxon, op. cit., PI. II. 



1. First zoija stage, immediately succeeding the stage figured on the preceding plate. VIII, I.X, X, rudimentary 



third inaxillipeds and first and second ambulatory apjiendages. The abdomen has six segments, the tclson 

 being not yet separated from the sixth somite. 



2. Tail of the same stage. The Arabic numerals indicate the liomology of the spines with those of the tail of 



the protozoiia (PI. XIII. fig. 17). 



3. First antenna of the same stage. 



4. Second antenna of the same stage, s p, spinous process corresponding to the spine on the second antenna of 



larvi-e of prawns (PI. XI. fig. 11, &c.) and Pagaridm (PI. .XII. fig. 22). r i\ sipiamiform process, homologous 

 to the external branch of the antenna of larval ilacroara, to the antennal scale of adult Macroura. Both of 

 these parts become aborted in the adult. The Hagellum (endopodite) of tlie second antenna of the adult is 

 wanting in the youngest zoea stages, or represented only by a small tubercle at the base of the sijuami- 

 forra process. 

 5-11. From Clans, Untersuchungen zur Erforschung der Genealogischen Grundlage des Crustaceen-Systems, 

 Taf. X., XI., Wien, 1876. 



5. Later zoea stage of a Portunid from Chili. 4 mm. long. This is probably the last zoea stage, preceding the 



megalopa. The first and second ma.xillipeds still serve as swimming oi'gans. The five ambulatory legs 

 (IX -XIII) are quite largely developed but still functionless. From the time of their first appearance 

 they are simple appendages destitute of external swimming branches. The chela is already prominent on 

 the first pair (IX). The second to the sixth abdominal somites are now provided with appendages. The 

 last pair (XIX) do not anticipate the others, as in Pacjiirus (PI. XII.) and most Macroura (e. g. Pcnriis, 

 PI. IX., Lucifer, PI. X.). 



6. First antenna of the same, re, outer branch. The inner flagellum, wanting in the earlier zoea stages, is 



developing as a sac-like process. 



7. Second antenna of the same. The flagellum (ri, wanting in fig. 4) is now quite well developed and seg- 



mented. 



8. Mandible of a younger zoea stage of a Brachyuran {Fissocciris) showing the commencement of the growth of 



the mandibular palp (e) which is wanting in the earliest zoea stage. 



9. Mandible of the late zoea stage of the Portunid represented in figs. 5-7. e, palpus. 



10. First maxilla of young zoea stage of y/iM poKte. 1, 2, basal joints (protopodite of Hu.xley). ri, endopodite 



in the form of a two-jointed palpus. 



11. Second maxilla of the same. 1, 2, basal joints or protopodite, each joint presenting a bilobcd blade, r >, 



endopodite, also bilobed. r e, exopodite or scaphognathite. 

 12-2(5. Cancer from Newport, K. I. From drawings by Faxon, July, 1879. 



12. Jlegalopa stage. Among the Brnchijura no scliizopod stage is fouml, but the zoea passes into the megalopa 



phase, in which most of the characters of the adult are seen. The abdomen, however, is largely developed, 

 and provided with swimming-feet. The megalopa stage of the Brachyuran corresponds very closely with 

 the adult Anomnuran. The maxillipeds are now converted into mouth parts, and the five Decapodal legs 

 have their full development. The caudal fork of the zoiia has become a telson plate similar to that of the 

 adult. The crossed lines on the left of the figure indicate the natural size. 



13. First antenna of the same. 



