312 CARL BOVALLIUS, AMPHIPODA HYPERIIDEA. I. 2. HYPERIID^E. 



Genus 8. THEMISTELLA, C. BOVALLIUS, 1887. 



Diagn. Caput mediocre, altius quam longius. Perceon leve: epimera cum segmentis coalita. Pedes 

 perm primi e't secundi parium cheliformes; carpus paullo dilatatus; processus carpalis an- 

 guste concavus in formam cochlearis redactus. Carpus pedum tertii ac quarti parium paullo 

 dilatatus, sed cum metacarpo instrumentum prensorium non formans. Pedes parium trium 

 ultimorum duobus prsecedentibus multo longiores, loDgitudine inasquales, pedes quinti paris 

 longissimi, sequentes longitudine sensim decrescentes; carpus pedum quinti paris non dila- 

 tatus; metacarpus modice elongatus. Pedes uri elongati. 



The head is moderately large, and is deeper than long. The pera>on is smooth; the epimerals 

 are coalesced with the segments. The first two pairs of peraeopoda are cheliform; the carpus 

 is a little dilated; the carpal process is narrowly concave, gouge-shaped. The carpus of 

 the third and fourth pairs is a little dilated, but does not form a folding hand together 

 with the metacarpus. The last three pairs are much longer than the third and fourth, 

 unequal in length, the fifth pair being the longest, and the following evenly decreasing in 

 length; the carpus of the fifth pair is not dilated; the metacarpus is moderately elongate. 

 The uropoda are elongated. 



Syil. 1887. Themistella, C. BOVALLIUS. "Systematical list of the Ampliipoda Hyperiidea». 



Bih. t. K. Sv. Vet. Ak. Handl. Bd. 11, N:o 16, 

 p. 22. 



The genus Themistella was instituted in order to receive a Hyperid which could 

 not properly be placed in any of the other genera. On the whole it is more closely 

 allied to Hyperia and Hyperiella than to Euthemisto, but differs decidedly in the chelate 

 character of the first pair of pereeopoda, and in the great length of the last three pairs. 

 From Euthemisto it is distinguished at once by the form of all the pairs of peraeopoda 

 except the second. From Parathemisto it differs in the same characteristics, in addition 

 to which comes the elongation of the fifth pair of peraeopoda. 



The type species was Themistella Steenstrupi, but I think that Dana's Le- 

 strigonus fuscus may also be conveniently placed in this genus, at least till it is better 

 known than at present. Hyperia pupa, A. Costa, which in 1887 *) I placed with a sign 

 of interrogation in the genus Hyperiella, in mistake for Themistella, because I did not 

 know it from the original description but onty from Spence Bate's »Catalogue» and Carus' 

 »Prodromus Faunas Mediterranean, does certainly not belong to the family Hyperiidse 

 but ought probably to be placed in the family Lycwidce as Stebbing suggested in 1888. 2 ) 



A. The second and third ural segments are coalesced as usual. The inner ramus 



of the first two pairs of uropoda is about half as long as the peduncle 1. Th. Steenstrupi. 



B. The second and third ural segments are free not coalesced. The inner ramus 



of the uropoda is a third part as long as the peduncle 2. Th. fusca. 



x ) In my "Systematical list of the Ampliipoda Hyperidea», p. 20. 



2 ) Th. Stebbing, »Report on the Amphipoda», Voy. of H. M. S. Challenger. Zoology. Vol. 29, p. 299. 



