A STEANGE CLAW 189 



seven eggs, which, as so commonly in deep-water species, 

 were extremely large. From one of these Mr. Spence 

 Bate extracted a young animal, and this proved to be not 

 unlike the young of the lobster at the same stage, but 

 more advanced, thus so far confirming the view that the 

 great size of the deep-water ova is in relation to the 

 more than usual advancement of the embryo before it is 

 hatched. 



Family 4. — Thaumastochelidce. 



The carapace is produced to a flattened point or ros- 

 trum. The first pair of antennae have on each peduncle 

 two long subequal flagella ; the second have a scale or 

 exopod. The first pair of trunk-limbs are chelate, un- 

 equal, somewhat unsymmetrical ; the small second pair 

 are chelate, subequal, symmetrical ; the outer branch of 

 the uropods is larger than the inner. The branchiae are 

 filamentous, cylindrical. 



To this family Spence Bate assigns only two genera, 

 one of which is British. 



Thawinastocheles, Wood-Mason, 1874, is appropriately 

 named ' the creature of wonderful claws.' The type spe- 

 cies, Thaumastocheles zaleucus (von Willemoes Suhm) (see 

 Plate X.), was taken by the Challenger from a depth of 450 

 fathoms in the West Indies, along with a great number of 

 other curious marine animals frequenting the globigerina 

 ooze in that locality. It is blind, and not only without eyes 

 but without eye-stalks, unless perchance the latter are re- 

 presented by a pair of tubercles projecting from the ' front.' 

 The ' front ' is sub-membranous and translucent, and Spence 

 Bate supposes that the optic nerve may terminate so 

 closely behind it as to receive impressions of light. But 

 though there are no eye-stalks, there are excavations 

 in the anterior margin of the carapace corresponding to 

 orbits, and also depressions in the first pair of antennas 

 such as eye-stalks often rest in. The inference then is 

 clear that eye- stalks once existent have been lost, and this 

 probably from their being detrimental instead of useful to 

 a burrowing creature. The burrowing character is in- 



