10-14. Pakcmonclcs vulgaris. From Yaxon, On t\\e'De\e\o\mKnt of Paltsmonetes vulgaris, PI. I., III., IV. Bull. 

 Mus. Comp. Zool., v., 1879. 



10. First larval (zoea) stage, ventral view. The three pairs of maxillipeds (VI-A''III) serve as swimming organs. 



Behind these are the rudiments of the two following pairs (IX, X). The hinder thoracic .somites are not 

 distinguishable, while the abdomen has six well-developed somites. Compare with this retardation in the 

 development of the thoracic region (which obtains generally among the higher Dcaipoda) the order of devel- 

 opment of the somites in the more primitive Dcaipoda like Pcneus (PI. IX.) and Lucifer (PI. X.), in the 

 Schizopoda (Euphausia, PI. VIII.), or in Apus (PI. VI.). These show the nonnal order of appearance of 

 the somites to be a regular sequence from before backwards. Tlie terminal segment of the body, which 

 represents the sLxth abdominal somite and the telson, ends in a broad plate instead of a fork like that iu the 

 larva of Pencus (PI. IX.). The caudal plate bears seven seta on each side. The line on the right indicates 

 the natural length of the larva. 



11. Fifth lai-val stage, cephalo-thorax viewed from below. All the thoracic legs are functional excepting the jie- 



nultimate pair (XII). All of them are two-branched excepting the last pair (XIII). 



12. Later laiTal stage,' seen from the side. The last thoracic legs lack e.xopodites. The telson is separated by a 



movable joint from the sixth somite of the abdomen. 



13. Rostrum of a later stage. 



14. Rostrum of adult. 



15-20. Pahancmcl.es variaiis, from fresh water, Italy. From Mayer, Carcinologische Mittheilungen. IX. Die 

 Metamorphosen von Pal amonctes varians Leach. Mitth. Zoolog. Station Neapel, II., Taf X., ISSO. This 

 species, which is also found in salt water in Northern Europe, has an abbreviated development compared 

 with P. vulgaris. In the first lanral stage it is furnished with the full number of functional cephalo- 

 thoracic appendages, the last three pairs being simple. The first five pairs of abdominal apjjendages are 

 also present in a rudimentary form. 



15. First maxilliped, first larval stage. 



16. First maxilliped, third stage. 



17. First maxilliped, fifth stage. 



18. First cheliped, first stage. 



19. First cheliped, third stage. 



20. First cheliped, fifth stage. 



21. Pdlu'inon Potiuna, a fresh-water prawn from Blumenau, Brazil, in the condition in which it leaves the efrg. 



All the appendages, including those of the abdomen, are present, as well as the gills. From a photograph 



of a drawing by lliiller. See Zoolog. Anzeig., III., p. 152, 1880. 

 22-37. Development of Xoricreto (/>«/«!!()■?«, ScJjllarus). 



22-25. From Glaus, Ueber einige Schizopoden und uiedere Malacostraken Messina's. Zeitsclir. wissensch. Zool., 

 XIIL, Taf XXV., XXVI., 1863. 



22. Embryo of Pnlinurus vulgaris before liatching. The body when extended measures about H uim. in length. 



The last two thoracic and all the abdominal appendages are wanting, ocl, ocellu.s. 



23. Young Phyllosoma larva (iScyllarus ?) 2 mm. long. The head and thorax now have tlie characteristic disk- 



shape of Phyllosoma. The abdomen is reduced to a rudiment, and the last two thoracic somites are no 

 longer distinguishable. The first maxillipeds are wanting in this stage. 



24. Oilier Phyllo.soma, 4 mm. long. The first maxillipeds (VI) are .sprouting out again, and rudiments of the 



la.st two pairs of thoracic appendages (XII, XIII) have appeared. 7, antennal gland. In the head are 

 seen the bilateral diverticula of the stomach, tlie median cephalic artery, and anteriorly the brain ganglion. 



25. Older Phyllosoma, 14 mm. long, 6i mm. broad. All the thoracic legs arc now developed and also the abdom- 



inal appendages. 

 26-37. From Kichters, Die Phyllosonien. Zeitschr. wissensch. Zool., XXIIL, Tuf. XXXI., XXXIL, 1S73. . 



26. Mandible of Phyllosoma (lar\-a of Palinurtis). 



27. Mandible of a Palinurus 25 mm. long. 5, palpus. 



28. Firet maxilla of Phyllosoma. 



29. First maxilla of a Palinurus 25 mm. long. 5, palpus. 



30. Second maxilla of Phyllosoma. re, scaphognathite. 



31. Second maxilla of a Palinurus, 25 mm. long. 



32. First maxilliped of Phyllosoma. re, exopodite. f, epipodite. 



33. First maxilliped of a Palinurus 25 mm. long. 



34. Abdominal appendage of Phyllosoma. 



35. Abdominal appendage of a young Palinurifs. 



36. Telson and last pair of abdominal apjiendages of Phyllosoma. 



37. Telson and last pair of abdominal appendages of a young Palinurus 25 mm. long. 



