FORMS ALLIED TO SARON 393 



Hippolytidae, Species R.S. I. 



Stage I. Length 3-9 mm. (Figs. 113, 114). 



Rostrum large, extending beyond antennules. Carapace as in Saron, with small 

 posterior tooth and anterior spine and marginal teeth. Pleura of abdominal somites 2-5 

 pointed. Telson narrow, as in Saron. 



Antennal scale a little broader than in S. marmoratus; endopod stout at base and 

 constricted at end into a denticulate spine. 



Exopods of maxillipedes 2 and 3 with four apical setae. 



Rudiments of legs 1-5 traceable. 



Stage II. Length 4-3-4-8 mm. (Figs. 115-117). 



Rostrum large, broadening at base over eyes. Carapace without supra-orbital spine ; 

 with large, bluntly pointed, process under eye. Telson unchanged except for additional 

 inner pair of spines. No anal spine. 



Antennule stout, peduncle segmented, with ventral spine, and slightly enlarged at 

 base with trace of stylocerite. Antennal scale with segmentation still traceable, and 

 17 inner and terminal setae; endopod stout with basal segment marked, and small 

 terminal spine; basis without spine. 



Legs I and 2 with incipient chelae; legs 1-3 with exopods bearing 8.6.6 setae; legs 4 

 and 5 rudimentary, leg 4 with rudiment of exopod. Pleopods present as small buds. 

 Rudiments of pleurobranchs on legs 1-4. 



The description is taken from a specimen moulted from stage I. 



Stage III. Length 5-4 mm. (Figs. 118-121). 



Telson nearly rectangular, slightly wider at end, the width about half the length; no 

 lateral spines; terminal spines 7+7. Anal spine absent. 



Antennule with small stylocerite; exopod with feathered seta and aesthetes in three 

 groups, but not segmented. Antennal scale unsegmented, without outer setae and 

 generally without outer apical spine. A very small spine seen in one specimen (Fig. 120). 

 Endopod nearly as long as scale. 



Legs I and 2 subchelate, leg 4 with exopod. Pleurobranchs large; rudiments of 

 epipods on maxillipede 2 and legs 1-4. Pleopods bilobed. Uropod, exopod with 14 

 setae; endopod small, not jointed to basis, with two small apical setae. 



To show how very much alike these different species of red carid larvae are I give a 

 figure (Fig. 122) of a second species, in stage IV, which can be distinguished by the form 

 of the rostrum and shape of the abdominal pleura. 



Stage IV. Length 5-3-6-7 mm. (Figs. 123-128). 



Rostrum in some cases with two small ventral teeth and one dorsal; carapace un- 

 changed, but with very small tooth in front of anterior dorsal papilla. Telson nearly or 

 quite three times as long as wide, narrowed at end, without lateral spines, and with 

 5+5 terminal spines. Anal spine absent. Antennule with stylocerite but no trace of 



