July 6, 1888.] 



SCIENTIFIC NEWS. 



11 



Natur al ffi fetorj?* 



A CURIOUS PARALLEL. 

 "THERE must be few zoologists who have not been greatly 

 -L struck by the manner in which types, so to speak, 

 of structure are reproduced in groups of animals widely 

 distant from one another. Thus we have beasts of prey 

 birds ot prey, fishes of prey, and insects of prey ; bur- 

 rowing mammals, burrowing reptiles, burrowing insects 

 and burrowing crustaceans ; swimming mammals, swim- 

 ming birds, swimming reptiles, and swimming insects ; 



Fig. r. 



A, Mantis rcligiosa and its larva. 

 mendica and its larva. 



B, Blepharis 



and similarity of habit implies similarity of structure, at 

 any rate so far as general principles are concerned. 

 And, very often, between individual species, though wide 

 as the poles asunder in the scale of nature, we find the 

 most startling similarity in bodily formation. Take, for 

 instance, the mole and the mole-cricket. One is a ver- 

 tebrate and the other an invertebrate ; yet not even the 

 most casual of observers can fail to notice the striking 

 likeness which exists between them. Take, again, the 

 whale and the fish : the similarity is so great that even 

 now many of us find it almost impossible to believe that 

 they do not belong to one and the same class of beings. 

 And examples such as these might be multiplied ad 



infinitum. There is one very remarkable case of natural 

 parallelism, however, with which very few of us are 

 acquainted, and which is sufficiently remarkable to call 

 for special notice ; and that is the instance of the Praying 

 Mantis and the Mantis Shrimp. 



The former of these— a member of the vast class of the 

 insects— is a fairly well-known creature. In some form 

 or other— for there are many species— it abounds in all 

 tropical and many temperate lands, and the curious 

 attitude which it adopts while waiting for food, and 

 which is referred to in its popular title, has rendered it 

 familiar to many who would otherwise never have heard 

 of its existence. This attitude, as most of us are no 

 doubt aware, is very much that of prayer, the long fore- 

 legs being clasped and raised aloft, as though in supplica- 

 tion to heaven. But, in reality, the insect is only holding 

 those limbs in readiness for the fatal stroke to be 

 delivered upon the first insect which ventures within 

 reach ; and, in order to understand the full utility of the 



Fig. 2. The Mantis Shrimp. Squilla mantis. 



position in question, we must examine the structure ot 

 the limbs. 



In the first place, then, as may be seen by the illus- 

 tration (fig. 1.), the coxa, or hip-joint, is greatly developed, 

 and becomes not merely a joint — as in the generality of 

 insects — but a veritable division of the limb, almost equal 

 to the thigh in size, and furnished with an immensely 

 powerful muscular system. The immediate effect of this 

 prolongation, of course, is greatly to lengthen the limb, 

 and at the same time to increase its power of folding. 

 In the mantis from which this description is written, and 

 which is a small one of its kind, the coxa is just three- 

 quarters of an inch in length, while the thigh is one- 

 eighth of an inch longer. 



The thigh itself, which, like the coxa, is triangular, is 

 armed upon its lower surface with two rows of strong 

 and sharp teeth, one upon the outer edge and one upon 

 the inner. In the specimen referred to the outer row 

 consists of four tolerably large teeth, placed rather widely 

 apart, and the inner of eighteen, varying in size, and 

 situated quite closely together. The lower leg is also 

 triangular, and is armed with a double row of teeth, the 

 inner consisting of thirteen and the outer of ten, while 



