ion 



THALARCTOa 



THALASSINHXE. 



Tkulamjjlorar, of the Exogens, in De Candolle's natural arrangement 

 [BEAR.] 



of plant*. 

 THAL 



HALARCTOS. 



THAL.VSSEMA. 



THALASSEUS. [SIEKSID.E.] 



THALASSlANa [OnMWU.1 



THALASSIANTHUS, a genus of Actinida. 



THALASSt'DROMA. [PBOCELLARIDA] 



THALASSI'XA. [TII.VI.ASSI.NID^.] 



TH ALASSIXID.E, a family of Macmrous Decapodous Crudaceu. 

 The species of this small but interesting family resemble each 

 other in appearance, and are remarkable for the extreme elongation 

 of their abdomen, and the email degree of consistence of their integu- 

 ment*. 



M. Milne-Edwards divides this family into two divisions : 

 1. Cryptobranchids. 



Under this group M. Milne- Edwards arranges all the Thalattin!d<c \ 

 which are without respiratory appendages suspended under the 

 abdomen. Their branchiaj are in general composed of cylinders, 

 united after the manner of a brush. All the species whose habits are 

 known live in the sand, in which they burrow deeply. 



GlaucotkBe, Edwards. Carapace nearly ovoid, and without any 

 nostriform prolongation; eyes projecting, large, and nearly pyriform; ' 

 internal antennas short, cylindrical, and bent ; external antennas 

 inserted lower than the preceding, their peduncle bent, and present- 

 ing above a small scale, the vestige of a palp. 



0. Permit is the only species known. It appears to inhabit the 

 seas of Asia. 



Callianatia, Leach. [CALHAXASSA.] 



Azia, Leach. Carapace very much compressed, and terminated 

 anteriorly by a small triangular rostrum ; ocular peduncles very small, 

 cylindrical, and terminated by a hemispherical cornea. Terminal 

 filaments of the internal antenna; nearly of the length of the 



.':.; ,.-.-. 



A.Slirkynehut is the only known species. Its length is about three 

 inches, and it inhabits the coasts of France and England. 



GMa tttllaio. 

 r, intermediate antenna ; 6, base of an external antenna. 



Thalatsina, Latreille. Carapace short, narrow, and very much 

 elevated. Stomachal region small, and limited backwards by a deep 

 furrow. Cardial and intestinal regions equally separated from the 

 branchial regions, and representing by their junction a triangle, the 

 apex of which is directed backwards. Front armed with a small 

 triangular rostrum. Eyes small and cylindrical. Internal antenna: 

 inserted above those organs; their peduncle of moderate size, and 

 their terminal filaments slender and unequal, the longest about thrice 

 the length of the peduncle. External antenna) very small ; their 

 peduncle cylindrical, hardly reaching beyond the rostrum, and pre- 

 senting above no vestige of appendages. 



T. scorpionidu. Length about inches. Colour brownish. It is n 

 native of the coasts of Chili. 



Aria 

 a, Intermediate antenna ; k, external antenna. 



OM* (Ottioi and Thalouina, Risso ; Oebia and Vpogebia, Leach). 

 Carapace terminating anteriorly by a triangular rostrum, and suffi- 

 ciently large to cover the eye* almost entirely ; on each side of its 

 base is tooth, which is continued with a crest, and forms the lateral 

 border of the upper surface of the stomachal region. Internal 

 antenna very short, but nevertheless their terminal filaments are 

 longer than their peduncle; external antcnnic very slender, and 

 presenting at their base no vestige of a moveable scale. 



O. tldlata. Length an inch and a half. It inhabits the coasts of 

 England. 



Thalauina icorpionidei. 



2. Qastrobranchids. 



M. Milne-Edwards observes that this small division of the Thalas- 

 sinians is very remarkable, for it eatablishe* the passage between tin' 

 Vallianaiift and th N/uiV/ic. In the general form of the body the 

 Crustaceans forming this division differ, he remarks, but very little 

 from the first, and the conformation of their thoracic bronchia; docs 

 not permit their separation from the Macrurous Decapods, nor their 

 distant removal from the Tbalaasininna ; but they have respiratory 

 appendages fixed to their abdominal false feet, exhibiting the greatest 

 analogy with the ramose branchiic of the Stomapods. 



Callianiilea (Edwards). Body very delicate, slender, and elongated; 

 carapace hardly a third of the length of the abdomen, and not covering 

 the last thoracic ring, compressed and rather elevated, its lower border 

 applied exactly against the base of the four first pain of feet. No 



