140 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 5 



unformed in the young of certain species; and, likewise, the spines of 

 the anterolateral angles of the carapace in the young of species in which 

 they are normally spined in fully developed or mature specimens may 

 appear blunt or merely rounded off in juvenile specimens. 



The characteristic coloration of the uropods in small Squillas is not 

 always well developed or so complete as in adults. 



Key to Species of Squilla Known from the Pacific Coast of America 



A^. No median carina on carapace anterior to level of cervical groove; 

 no intermediate carinae ; and laterals, if present, placed well back 

 on carapace, often inconspicuous. 



Lateral margins of 6th and 7th thoracic somites not bilobed. Submedian 

 carinae present on 6th abdominal somite, posteriorly spined. No man- 

 dibular palp. Epipodites on first 4 thoracic limbs only (for iS*. gracilipes 

 the count is not known). Telson without trace of pre- (or second) lateral 

 lobe or angle. 



B^. Raptorial dactylus with 4 teeth or spines, counting the terminal 

 one. 



Cornea placed obliquely on eyestalk. Lateral margins of 6th and 7th 

 thoracic somites rounded. No submedian carinae on somites anterior 

 to 6th abdominal. 



G^. Lateral process of 5th (first free) thoracic somite a promi- 

 nent, flattened spine or lobe distally more or less rounded 

 oflF or subacute, with apex directed forward or laterally ; a 

 pair of ventral spines also present. 



Anterolateral angles of carapace spined. Telson without carinae 

 either side of median one except marginals. Denticles 6, 8-14, 1, 

 all very sharp, spiniform polita, p. 146 



C^. Lateral margin of 5th thoracic somite in dorsal view appears 

 bilobed, neither lobe forming a conspicuous lateral process : 

 a pair of ventral spines or sharp angles present. 



Anterolateral angles of carapace unarmed. Telson with 5 more or 

 less complete longitudinal carinae either side of median one. 

 Denticles 4-5, 9-11, 1 swetti, p. 146 



Fig. 1. Diagrammatic sketches of Squilla, illustrating terms used 

 in description, a. carapace and rostrum, exposed thoracic so- 

 mites, and first abdominal somite; b. 5th and 6th abdominal so- 

 mites and telson. 



