10-14. Palemonetes vulgaris. From Faxon, On the Development of Pulamonetes vulgaris, Pl. 1., 111.,1V. Bull. 
Mus. Comp. Zool., V., 1879. 
10. First larval (zoéa) stage, ventral view. The three pairs of maxillipeds (VI-VIII) serve as swimming organs. 
Behind these are the rudiments of the two following pairs (IX, X). The hinder thoracie 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 Decapoda) the order of devel- 
opment of the somites in the more primitive Decapoda like Peneus (Pl. IX.) and Lucifer (Pl. X.), in the 
Schizopoda (Euphausia, Pl. VILIL.), or in Apus (Pl. VI.). These show the normal order of appearance of 
the somites to be a regular sequence from before backwards. The terminal segment of the body, which 
represents the sixth abdominal somite and the telson, ends in a broad plate instead of a fork like that in the 
larva of Pencus (Pl. IX.). The caudal plate bears seven sete on each side. The line on the right indicates 
the natural length of the larva. 
11. Fifth larval stage, cephalo-thorax viewed from below. All the thoracic legs are functional excepting the pe- 
nultimate pair (XII). Allof them are two-branched excepting the last pair (XIII). 
12. Later larval stage, seen from the side. The last thoracic legs lack exopodites. 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. Puleemonetes varians, from fresh water, Italy. From Mayer, Carcinologische Mittheilungen. IX. Die 
Metamorphosen von Palemonetes varians Leach. Mitth. Zoolog. Station Neapel, I1., Taf. X., 1880. This 
species, which is also found in salt water in Northern Europe, has an abbreviated development compared 
with P. vulgaris. In the first larval 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 appendages 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. Palemon Potiuna, a fresh-water prawn from Blumenau, Brazil, in the condition in which it leaves the egg. 
All the appendages, including those of the abdomen, are present, as well as the gills. From a photograph 
of a drawing by Miiller. See Zoolog. Anzeig., III., p. 152, 1880. 
Development of Loricata (Palinwrus, Scyllarus). 
From Claus, Ueber einige Schizopoden und niedere Malacostraken Messina’s. Zeitschr. wissensch. Zool., 
XIII., Taf. XXV., XXVI., 1863. 
22. Embryo of Palinwrus vulgaris before hatching. The body when extended measures about 14 mm. in length. 
The last two thoracic and all the abdominal appendages are wanting. oc/, ocellus. 
23. Young Phyllosoma larva (Scyl/wrus ?) 2mm. long. The head and thorax now have the 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. Older Phyllosoma, 4mm. long. The first maxillipeds (VI) are sprouting out again, and rudiments of the 
last two pairs of thoracic appendages (XII, XIII) have appeared. y, antennal gland. In the head are 
seen the bilateral diverticula of the stomach, the median cephalic artery, and anteriorly the brain ganglion. 
25. Older Phyllosoma, 14 mm. long, 64 mm. broad. All the thoracic legs are now developed and also the abdom- 
inal appendages. 
26-37. From Richters, Die Phyllosomen. Zeitschr. wissensch. Zool., XXIII., Taf. XXXI., XXXII, 1873. 
26. Mandible of Phyllosoma (larva of Palinwrus). 
7. Mandible of a Palinurus 25 mm. long. 4, palpus. 
8. First maxilla of Phyllosoma. 
rp Ww bt 
29. First maxilla of a Palinurus 25 mm. long. 6, palpus. 
30. Second maxilla of Phyllosoma. 7, scaphognathite. 
31. Second maxilla of a Palinwrus, 25 mm. long. 
32. First maxilliped of Phyllosoma. 7 e, exopodite. €, epipodite. 
33. First maxilliped of a Palinurus 25 mm. long. 
34. Abdominal appendage of Phyllosoma. 
35. Abdominal appendage of a young Palinurus. 
36. Telson and last pair of abdominal appendages of Phylosoma. 
37. Telson and last pair of abdominal appendages of a young Palinwrus 25 mm. long. 
