28 



The Ottawa Naturalist 



[May 



left rim of the ends; in no case is there anything 

 remaining of the constricted middle portion, so that 

 what is present is made up of a series of partial ends 

 in couples, each pair being contributed to by an 

 anterior vertebral end and a posterior end of the 

 vertebra next in front. Where the vertebrae have 

 been fully removed their impressions are left in the 

 shagreen, or where erosion has been most severe the 

 shagreen itself has disappeared. 



Toward the anterior end of the series the vertebrae 

 are about 5 mm. high, and 3.5 mm. long, with ten 

 in a space of about 35 mm. There is a gradual 

 diminution in size posteriorly in the series, until, in 

 the hinder half of the tail, there are thirteen verte- 

 bral bodies m an equal space. 



The granular shagreen tubercles are minute, of 

 one size, nearly square with rounded angles, and lit 

 closely together, four occurring in a space of 1 mm. 

 As seen from within they are decidedly convex or 

 tumid, and have the appearance of being nearly 

 circular in outline. Each tubercle has, in this 

 aspect, a central, circular opening or depression. In 

 what appears to be an external view they are some- 

 what more regularly four-sided, convex, and appar- 

 ently devoid of sculpture. 



The anal fin is subtriangular in lateral aspect, 

 nearly twice as long as deep, and broadly rounded 

 below. In it the shagreen is preserved mainly along 

 the basal line, and the free edges. The caudal lobe 

 is long, with a maximum depth about equal to that 

 of the anal fin. Its length is over five times its 

 depth, and throughout the shagreen is present, sharply 

 defining the sweeping curve of the lower margin. 

 Above the base of the caudal lobe the shagreen in 

 the specimen, passes up behind the spinal column 

 and ends dorsally in a definite longitudinal line a 

 short distance (about 6 mm. at the midlength of the 

 tail) above the vertebrae. In the shagreen surface 

 above the posterior caudal vertebrae obscure parallel 

 markings, directed obliquely upward and backward, 

 may indicate the presence of fin-supports, appar- 

 ently one to each vertebra. Superiorly, above the 

 anal fin, an indefiniteness in the dorsal outline sug- 

 gests the possible position of a dorsal fin which might 

 be expected in this neighbourhood. From slightly 

 in advance of here to the forward end of the 

 specimen the dorsal outline is not preserved. 



This specimen has much the same size and pro- 

 portions as Palaeospinax priscus (Agassiz) as de- 

 scribed and figured by Smith Woodward from the 

 Lower Lias of Dorset.* It differs from that species 

 in having the anal fin close to the caudal, in the 

 vertebrae being smaller, and the granules of the 



shagreen of one size only. For the very slender 

 species represented the name ejuncidus is proposed. 

 In view of the fact that this interesting specimen 

 supplies no information regarding the dorsal fins, and 

 therefore as to whether they have spines or not, the 

 assignment of the species to the genus Palaeospinax 

 is a provisional measure only until we have further 

 knowledge of its structure. 



UNUSUAL NESTING MATERIAL USED 

 BY PURPLE MARTINS. 



*Cat. Fcssil Fishes Brit. Mus. pt. 1. 1889, p. .32.3, 

 pi. YII, fig. 1. 



The birds, like human beings, have in their midst 

 eccentric individuals that deviate from the path of 

 custom to do the unusual. In some cases no doubt 

 these unusual acts, induced by various causes, gradu- 

 ally become more usual and eventually customary. 

 For instance, man-made sites, from being the un- 

 usual, have become the usual nesting places of the 

 Purple Martins; and furthermore it appears that 

 these birds are about to take another step in their 

 evolution by adopting man-made nesting material. 

 As evidence I submit the following list of material 

 taken from one compartment of my martin house: 



36 bits of window glass. 

 33 flat bits of rock. 



9 pieces of clam shell. 



4 scraps of tin roofing. 



6 nails 1 to 4 inches. 



1 slate pencil. 



1 bit of dry orange peel. 



1 safety pin. 



1 pint of the usual twigs, dead grass and green 

 leaves elm in this case. 



Probably one or both builders of this unusual 

 nest had been hatched or had formerly nested in 

 some congested city where the usual nesting material 

 was not procurable, only such as listed above being 

 available, and in spite of the fact that grass, twigs 

 and green leaves were plentiful in my neighbour- 

 hood, this inherited or acquired conception of nest 

 building had persisted. 



The male bird of this 20th century couple, which 

 built a home of stone and glass and furnished it with 

 a safety pin and a slate pencil (evidently intended 

 sending their "little troubles" to school), had not 

 attained the age of purple plumage, still being light 



breasted. 



Clyde L. Patch. 

 Ottawa. 



