312 BULLETIN OF THE 



Just behind the eye-stalks, on the front part of the carapace, are two 

 large blotches of dark pigment. Two similar pigment-spots are seen in 

 most individuals on the hinder part of the carapace, and one in the 

 median line of the body on the dorsal side of the second abdominal seg- 

 ment. The distribution of pigment-spots varies considerably, however, 

 in different individuals. 



Second Larval Stage (PI. II. Figs. 2-4). — After the first moult the 

 larva measures 3 mm. from the tip of the rostrum to the end of the 

 abdomen. It now has the the same general shape as in the preceding 

 stage, but the carapace is provided with a dorsal spine which is directed 

 forward at the base of the rostrum, and a lateral spine on each side, on 

 the anterior margin. This spine is the supra-orbital of Stimpson's 

 nomenclature.* The posterior margin of the fifth abdominal segment is 

 produced into a tooth-like process on each side. 



The first pair of antennae have acquired an additional (third) segment, 

 but are still simple. 



The second pair of antennae are of the same shape as in the first 

 larval stage, as are also the mandibles and maxillae. 



The maxillipeds have increased in length, and the second and third 

 pairs are longer in proportion to the first pair than they were in the 

 foregoing stage. The first pair have gained a segment in both the inner 



Arter. Kongel. Dansk. Vidensk. Selsk. naturvid. og mathem. Afhandl. IX Deel, 

 pp. 245 - 251, Tab. VI. Figs. 120-132. 1849), the young of Hippolyte polaris ex- 

 tracted from the egg have the five pairs of walking-feet in the form of small, simple, 

 jointed appendages, the first pair with the chela already formed. Five pairs of 

 double abdominal limbs are also present, but no sign of the sixth or posterior pair. 



We thus see among the Garidea a very great difference in the degree of develop- 

 ment in which the larvae leave the egg. At one extreme we have Peneus cpiitting 

 the egg as a nauplius (Fritz Miiller, Die Verwandlung der Garneelen. Arch. f. 

 Naturg. , Vol. XXIX. pp. 8 - 23, Taf. II. 1863), at the other Hippolyte, provided with 

 all the appendages of the adult excepting the last abdominal. Here the walking-feet 

 are simple from the first, and the larva does not pass through a Schizopod stage. 

 Between these extremes are larvae like those of Caridina (Joly), Palcemonctes, etc., 

 which hatch with appendages developed as far back as the third pair of maxillipeds 

 inclusive, or the second pair of walking-feet, and which pass through a Mysis-st&te. 



It is to be observed, however, that in the larva doubtfully referred to Hippolyte, by 

 Claus (Untersuchungen zur Erforsehung der Genealogischen Grundlage des Crustaceen- 

 Systems, pp. 44, 45, Figs. 14-18. 1876), the rudiments of the walking-feet appear 

 subsequently to the earliest larval stage, — first the two anterior pairs simultaneous 

 with the swimmerets (the earliest to appear of the abdominal limbs), then the three 

 following pairs. Here all the walking-feet of the adult are split-feet in the larva. 



* Prodromus Descriptionis Animalium Evertebratorum, etc. Proc. Acad. Nat. Sci. 

 Phila., 1860, p. 24. 



