70 
THE VOYAGE OF H.M.S. CHALLENGER. 
Milne-Edwards’ figures of Gonodcictylus folinii, and as it also fails to agree perfectly with, 
his and Miers’ descriptions, it must for the present at least be regarded as a distinct’ 
species, differing from Protosquilla ( Gonodcictylus ) folinii in the following points : — 
Antero-lateral angles of rostrum simple in Protosquilla folinii, double in Protosquilla 
elongata. Posterior margin of telson with three rounded spines on each side of the deep 
median notch in Protosquilla ( Gonodactylus) folinii, and a single obtusely rounded lobe 
in Protosquilla elongata. 
If A. Milne-Edwards’ figures are trustworthy the two species also differ in the, 
following features : — First antennse very long in Protosquilla folinii, short in Protosquilla 
elongata. No spine on anterior edge of basal joint of second antenna in Protosquilla 
folinii, a long spine in Protosquilla elongata. Carapace nearly as wide as long, 
rectangular, and with rounded antero- and postero-lateral angles in Protosquilla folinii ; 
elongated, emarginated, narrow anteriorly, and with antero-lateral angles acute in 
Protosquilla elongata. Thoracic and abdominal somites rounded in Protosquilla folinii ; 
lateral margins of thoracic somites of Protosquilla elongata truncated, and postero-lateral 
angles of abdominal somites acute. 
The species is of great interest as it and the closely related Protosquilla folinii 
are the most primitive forms which are known among the Stomatopods, exhibiting 
the embryonic or larval features which are characteristic of the genus, such as the 
fusion of the telson with the sixth abdominal somite, the small size of the uropods, and 
the presence of three long spines on the rostrum; without exhibiting any of the remark- 
able modifications of the posterior end of the body which are so strikingly characteristic 
of most of the species of the genus. The telson of an ordinary Squilla, that of Coronis, 
or that of the most aberrant Protosquilla, such as Protosquilla guerinii, may all be 
derived from that of Protosquilla folinii by very slight changes, and the carapace of 
Protosquilla elongata might be readily modified into that of a true Squilla, while it is 
also very similar to the flat square carapace of the other members of its own genus. 
2. Protosquilla folinii (Milne-Edwards). 
Gonodactylus folinii, A. Milne-Edwards, Obs. sur la Fauna Carcinol. des lies du Cap-Vert, 
Nouv. Arch. Mus. Hist. Nat., t. iv. 1868, p. 65, pi. xviii. figs. 8-11. 
Gonodactylus Folinii, Miers, E. J., On the Squillidse, Ann. and Mag. Nat. Hist., ser. 5, vol. v., 
1880, p. 123. 
Diagnosis. — Protosquilla with the rostrum ending in a long slender acute 
median spine, and on each side of this a single acute antero-lateral spine which is directed 
outwards and forwards and is a little shorter than the median spine. Carapace with 
rounded antero- and postero-lateral angles. First five abdominal somites smooth, 
Dorsal surface of sixth abdominal somite with four rounded tubercles, the outer ones 
